Electric vehicles have a DC motor powered by a bank of batteries. Motor speed is increased by placing additional batteries in the motor circuit. It is desireable to connect the batteries to the motor so the energy drawn for the individual batteries is about the same. Various means have been employed to achieve the desired sequencing of the battery connections. The present invention utilizes the capabilities of a microprocessor to control a flip-flop (alternate action or sequencing) solenoid.
"False" sequencing of the solenoid can occur when the foot pedal (accelerator) is released suddenly causing the associated switch to bounce. This previously required a damper on the switch which added cost.
An inherent defect in the prior art lies in the fact that the motor current flows through the main solenoid and the flip-flop solenoid. For cost reasons, the flip-flop solenoid is not as robust as the main solenoid. Therefore, the flip-flop can be damaged if required to switch heavy DC current. The flip-flop "drops out" (opens) in a longer time than the main solenoid so it is inherently protected on opening. But, there is nothing in the art assuring closing the main solenoid after the flip-flop.
Attention is directed to the following patents:
______________________________________ Pat. No. Issue Date ______________________________________ United States 4,093,896 June 6, 1978 4,131,833 Dec. 26, 1978 4,283,668 Aug. 11, 1981 Canadian 1,131,299 Sept. 7, 1982 ______________________________________